Phase-field modeling of γ′-precipitate shapes in nickel-base superalloys and their classification by moment invariants
Phase-field modeling of γ′-precipitate shapes in nickel-base superalloys and their classification by moment invariants
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DOI：
10.1140/epjb/e2019-100256-1
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发表时间：
2019-09-01
影响因子：
1.6
通讯作者：
Fleck, Michael
中科院分区：
文献类型：
--
作者：
Holzinger, Markus;Schleifer, Felix;Fleck, Michael
本文建立了一个模拟镍基高温合金中析出相微观结构形成的相场模型。该模型考虑了非均匀和各向异性弹性变形的局部效应，这主要是由于析出相和基体相之间的晶格失配造成的。此外，在每一个时间步，我们认为沉淀物熟化的化学驱动力瞬间平衡到一个均匀的值，导致守恒相体积。该模型被应用于研究一个二维单γ '粒子嵌入在不同的晶格失配和γ/γ'界面能的γ矩阵的平衡形状。此外，我们应用矩不变量的方法来量化所得到的沉淀物的平衡形状，这原来是一个尺寸独立的表征的颗粒形状。实验以及模拟粒子形状的二维不变矩的结果值进行了讨论和比较。考虑到理想的球形粒子，我们发现，大的值的伽玛/伽玛'-接口宽度导致系统偏差的矩不变量。
We develop a phase-field model for the simulation of precipitate microstructure pattern formation in nickel-base superalloys. The model accounts for the local effects from inhomogeneous and anisotropic elastic deformations, which mainly result from the lattice misfit between the precipitates and matrix phase. Further, in each time-step, we consider the chemical driving force for precipitate ripening to instantaneously equilibrate to a homogeneous value, leading to conserved phase volumes. The model is applied to study the equilibrium shape of a 2D single gamma '-particle embedded in the gamma-matrix with varying lattice misfit and gamma/gamma ' interface energies. Further, we apply the method of moment invariants to quantify the resulting equilibrium shapes of precipitates, which turns out to be a size independent characterization of the particle shape. Resulting values for the 2D moment invariants of experimental as well as simulated particle shapes are discussed and compared. Considering ideally spherical particles, we find that large values for the gamma/gamma '-interface width lead to systematic deviations in the resulting moment invariants.